src/main/java/com/google/devtools/build/lib/skyframe/BzlLoadValue.java - bazel - Git at Google

 // Copyright 2014 The Bazel Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //    http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 package com.google.devtools.build.lib.skyframe;

 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Interner;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.concurrent.BlazeInterners;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
 import com.google.devtools.build.lib.syntax.Module;
 import com.google.devtools.build.lib.vfs.Root;
 import com.google.devtools.build.lib.vfs.RootedPath;
 import com.google.devtools.build.skyframe.SkyFunctionName;
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
 import java.util.Objects;

 /**
  * A value that represents the .bzl module loaded by a Starlark {@code load()} statement.
  *
  * <p>The key consists of an absolute {@link Label} and the context in which the load occurs. The
  * Label should not reference the special {@code external} package.
  */
 public class BzlLoadValue implements SkyValue {

   private final Module module; // .bzl module (and indirectly, the entire load DAG)
   private final byte[] transitiveDigest; // of .bzl file and load dependencies

   @VisibleForTesting
   public BzlLoadValue(Module module, byte[] transitiveDigest) {
     this.module = Preconditions.checkNotNull(module);
     this.transitiveDigest = Preconditions.checkNotNull(transitiveDigest);
   }

   /** Returns the .bzl module. */
   public Module getModule() {
     return module;
   }

   /** Returns the digest of the .bzl module and its transitive load dependencies. */
   public byte[] getTransitiveDigest() {
     return transitiveDigest;
   }

   private static final Interner<Key> keyInterner = BlazeInterners.newWeakInterner();

   /** SkyKey for a Starlark load. */
   abstract static class Key implements SkyKey {

     /**
      * Returns the label of the .bzl file to be loaded.
      *
      * <p>For {@link KeyForBuiltins}, it usually begins with {@code @builtins//:}. Other values are
      * possible but indicate a bug in the {@code @builtins} .bzl files and will fail during
      * evaluation.
      */
     abstract Label getLabel();

     /**
      * Constructs a new key suitable for evaluating a {@code load()} dependency of this key's .bzl
      * file.
      *
      * <p>The new key uses the given label but the same contextual information -- whether the
      * top-level requesting value is a BUILD or WORKSPACE file, and if it's a WORKSPACE, its
      * chunking info.
      */
     abstract Key getKeyForLoad(Label loadLabel);

     /**
      * Constructs an ASTFileLookupValue key suitable for retrieving the Starlark code for this .bzl,
      * given the Root in which to find its file.
      */
     abstract ASTFileLookupValue.Key getASTKey(Root root);

     @Override
     public SkyFunctionName functionName() {
       return SkyFunctions.BZL_LOAD;
     }
   }

   /** A key for loading a .bzl during package loading (BUILD evaluation). */
   @Immutable
   @AutoCodec.VisibleForSerialization
   static final class KeyForBuild extends Key {

     private final Label label;

     /**
      * True if this is the special prelude file, whose declarations are implicitly loaded by all
      * BUILD files.
      */
     private final boolean isBuildPrelude;

     private KeyForBuild(Label label, boolean isBuildPrelude) {
       this.label = Preconditions.checkNotNull(label);
       this.isBuildPrelude = isBuildPrelude;
     }

     @Override
     Label getLabel() {
       return label;
     }

     @Override
     Key getKeyForLoad(Label loadLabel) {
       // Note that the returned key always has !isBuildPrelude. I.e., if the prelude file loads
       // another .bzl, the loaded .bzl is processed as normal with no special prelude magic. This is
       // because 1) only the prelude file, not its dependencies, should automatically re-export its
       // loaded symbols; and 2) we don't want prelude-loaded modules to end up cloned if they're
       // also loaded through normal means.
       return keyForBuild(loadLabel);
     }

     @Override
     ASTFileLookupValue.Key getASTKey(Root root) {
       if (isBuildPrelude) {
         return ASTFileLookupValue.keyForPrelude(root, label);
       } else {
         return ASTFileLookupValue.key(root, label);
       }
     }

     @Override
     public String toString() {
       return label.toString();
     }

     @Override
     public boolean equals(Object obj) {
       if (this == obj) {
         return true;
       }
       if (!(obj instanceof KeyForBuild)) {
         return false;
       }
       KeyForBuild other = (KeyForBuild) obj;
       return this.label.equals(other.label) && this.isBuildPrelude == other.isBuildPrelude;
     }

     @Override
     public int hashCode() {
       return Objects.hash(KeyForBuild.class, label, isBuildPrelude);
     }
   }

   /**
    * A key for loading a .bzl during WORKSPACE evaluation.
    *
    * <p>This needs to track "chunking" information, i.e. a sequence number indicating which segment
    * of the WORKSPACE file we are in the process of evaluating. This helps determine the appropriate
    * repository remapping value to use.
    */
   // TODO(brandjon): Question: It looks like the chunk number doesn't play any role in deciding
   // whether or not a repo is available for load()ing. Are we tracking incremental dependencies
   // correctly? For instance, if a repository declaration moves from one workspace chunk to another,
   // are we reevaluating whether its loads are still valid? AI: fix if broken, improve this comment
   // if not broken.
   @Immutable
   @AutoCodec.VisibleForSerialization
   static final class KeyForWorkspace extends Key {

     private final Label label;
     private final int workspaceChunk;
     private final RootedPath workspacePath;

     private KeyForWorkspace(Label label, int workspaceChunk, RootedPath workspacePath) {
       this.label = Preconditions.checkNotNull(label);
       this.workspaceChunk = workspaceChunk;
       this.workspacePath = Preconditions.checkNotNull(workspacePath);
     }

     @Override
     Label getLabel() {
       return label;
     }

     int getWorkspaceChunk() {
       return workspaceChunk;
     }

     RootedPath getWorkspacePath() {
       return workspacePath;
     }

     @Override
     Key getKeyForLoad(Label loadLabel) {
       return keyForWorkspace(loadLabel, workspaceChunk, workspacePath);
     }

     @Override
     ASTFileLookupValue.Key getASTKey(Root root) {
       return ASTFileLookupValue.key(root, label);
     }

     @Override
     public String toString() {
       return label + " (in workspace)";
     }

     @Override
     public boolean equals(Object obj) {
       if (this == obj) {
         return true;
       }
       if (!(obj instanceof KeyForWorkspace)) {
         return false;
       }
       KeyForWorkspace other = (KeyForWorkspace) obj;
       return label.equals(other.label)
           && workspaceChunk == other.workspaceChunk
           && workspacePath.equals(other.workspacePath);
     }

     @Override
     public int hashCode() {
       return Objects.hash(KeyForWorkspace.class, label, workspaceChunk, workspacePath);
     }
   }

   /**
    * A key for loading a .bzl during {@code @builtins} evaluation.
    *
    * <p>This kind of key is only requested by {@link StarlarkBuiltinsFunction} and its transitively
    * loaded {@link BzlLoadFunction} calls.
    *
    * <p>The label begins with {@code @builtins//:}, but it is distinct from any .bzl in an external
    * repository named {@code "@builtins"}.
    */
   @Immutable
   @AutoCodec.VisibleForSerialization
   static final class KeyForBuiltins extends Key {

     private final Label label;

     private KeyForBuiltins(Label label) {
       this.label = Preconditions.checkNotNull(label);
     }

     @Override
     Label getLabel() {
       return label;
     }

     @Override
     Key getKeyForLoad(Label label) {
       return keyForBuiltins(label);
     }

     @Override
     ASTFileLookupValue.Key getASTKey(Root root) {
       return ASTFileLookupValue.key(root, label);
     }

     @Override
     public String toString() {
       return label + " (in builtins)";
     }

     @Override
     public boolean equals(Object obj) {
       if (this == obj) {
         return true;
       }
       if (!(obj instanceof KeyForBuiltins)) {
         return false;
       }
       return this.label.equals(((KeyForBuiltins) obj).label);
     }

     @Override
     public int hashCode() {
       return Objects.hash(KeyForBuiltins.class, label);
     }
   }

   /** Constructs a key for loading a regular (non-workspace) .bzl file, from the .bzl's label. */
   static Key keyForBuild(Label label) {
     return keyInterner.intern(new KeyForBuild(label, /*isBuildPrelude=*/ false));
   }

   /**
    * Constructs a key for loading a .bzl file from the context of evaluating the WORKSPACE file.
    *
    * @param label the label of the bzl file being loaded
    * @param workspaceChunk the workspace chunk that the load statement originated from. If the bzl
    *     file is loaded more than once, this is the chunk that it was first loaded from
    * @param workspacePath the path of the workspace file for the project
    */
   static Key keyForWorkspace(Label label, int workspaceChunk, RootedPath workspacePath) {
     return keyInterner.intern(new KeyForWorkspace(label, workspaceChunk, workspacePath));
   }

   /** Constructs a key for loading a .bzl file within the {@code @builtins} pseudo-repository. */
   static Key keyForBuiltins(Label label) {
     return keyInterner.intern(new KeyForBuiltins(label));
   }

   /** Constructs a key for loading the special prelude .bzl. */
   static Key keyForBuildPrelude(Label label) {
     return keyInterner.intern(new KeyForBuild(label, /*isBuildPrelude=*/ true));
   }
 }
	// Copyright 2014 The Bazel Authors. All rights reserved.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.
	package com.google.devtools.build.lib.skyframe;

	import com.google.common.annotations.VisibleForTesting;
	import com.google.common.base.Preconditions;
	import com.google.common.collect.Interner;
	import com.google.devtools.build.lib.cmdline.Label;
	import com.google.devtools.build.lib.concurrent.BlazeInterners;
	import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
	import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
	import com.google.devtools.build.lib.syntax.Module;
	import com.google.devtools.build.lib.vfs.Root;
	import com.google.devtools.build.lib.vfs.RootedPath;
	import com.google.devtools.build.skyframe.SkyFunctionName;
	import com.google.devtools.build.skyframe.SkyKey;
	import com.google.devtools.build.skyframe.SkyValue;
	import java.util.Objects;

	/**
	* A value that represents the .bzl module loaded by a Starlark {@code load()} statement.
	*
	* <p>The key consists of an absolute {@link Label} and the context in which the load occurs. The
	* Label should not reference the special {@code external} package.
	*/
	public class BzlLoadValue implements SkyValue {

	private final Module module; // .bzl module (and indirectly, the entire load DAG)
	private final byte[] transitiveDigest; // of .bzl file and load dependencies

	@VisibleForTesting
	public BzlLoadValue(Module module, byte[] transitiveDigest) {
	this.module = Preconditions.checkNotNull(module);
	this.transitiveDigest = Preconditions.checkNotNull(transitiveDigest);
	}

	/** Returns the .bzl module. */
	public Module getModule() {
	return module;
	}

	/** Returns the digest of the .bzl module and its transitive load dependencies. */
	public byte[] getTransitiveDigest() {
	return transitiveDigest;
	}

	private static final Interner<Key> keyInterner = BlazeInterners.newWeakInterner();

	/** SkyKey for a Starlark load. */
	abstract static class Key implements SkyKey {

	/**
	* Returns the label of the .bzl file to be loaded.
	*
	* <p>For {@link KeyForBuiltins}, it usually begins with {@code @builtins//:}. Other values are
	* possible but indicate a bug in the {@code @builtins} .bzl files and will fail during
	* evaluation.
	*/
	abstract Label getLabel();

	/**
	* Constructs a new key suitable for evaluating a {@code load()} dependency of this key's .bzl
	* file.
	*
	* <p>The new key uses the given label but the same contextual information -- whether the
	* top-level requesting value is a BUILD or WORKSPACE file, and if it's a WORKSPACE, its
	* chunking info.
	*/
	abstract Key getKeyForLoad(Label loadLabel);

	/**
	* Constructs an ASTFileLookupValue key suitable for retrieving the Starlark code for this .bzl,
	* given the Root in which to find its file.
	*/
	abstract ASTFileLookupValue.Key getASTKey(Root root);

	@Override
	public SkyFunctionName functionName() {
	return SkyFunctions.BZL_LOAD;
	}
	}

	/** A key for loading a .bzl during package loading (BUILD evaluation). */
	@Immutable
	@AutoCodec.VisibleForSerialization
	static final class KeyForBuild extends Key {

	private final Label label;

	/**
	* True if this is the special prelude file, whose declarations are implicitly loaded by all
	* BUILD files.
	*/
	private final boolean isBuildPrelude;

	private KeyForBuild(Label label, boolean isBuildPrelude) {
	this.label = Preconditions.checkNotNull(label);
	this.isBuildPrelude = isBuildPrelude;
	}

	@Override
	Label getLabel() {
	return label;
	}

	@Override
	Key getKeyForLoad(Label loadLabel) {
	// Note that the returned key always has !isBuildPrelude. I.e., if the prelude file loads
	// another .bzl, the loaded .bzl is processed as normal with no special prelude magic. This is
	// because 1) only the prelude file, not its dependencies, should automatically re-export its
	// loaded symbols; and 2) we don't want prelude-loaded modules to end up cloned if they're
	// also loaded through normal means.
	return keyForBuild(loadLabel);
	}

	@Override
	ASTFileLookupValue.Key getASTKey(Root root) {
	if (isBuildPrelude) {
	return ASTFileLookupValue.keyForPrelude(root, label);
	} else {
	return ASTFileLookupValue.key(root, label);
	}
	}

	@Override
	public String toString() {
	return label.toString();
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (!(obj instanceof KeyForBuild)) {
	return false;
	}
	KeyForBuild other = (KeyForBuild) obj;
	return this.label.equals(other.label) && this.isBuildPrelude == other.isBuildPrelude;
	}

	@Override
	public int hashCode() {
	return Objects.hash(KeyForBuild.class, label, isBuildPrelude);
	}
	}

	/**
	* A key for loading a .bzl during WORKSPACE evaluation.
	*
	* <p>This needs to track "chunking" information, i.e. a sequence number indicating which segment
	* of the WORKSPACE file we are in the process of evaluating. This helps determine the appropriate
	* repository remapping value to use.
	*/
	// TODO(brandjon): Question: It looks like the chunk number doesn't play any role in deciding
	// whether or not a repo is available for load()ing. Are we tracking incremental dependencies
	// correctly? For instance, if a repository declaration moves from one workspace chunk to another,
	// are we reevaluating whether its loads are still valid? AI: fix if broken, improve this comment
	// if not broken.
	@Immutable
	@AutoCodec.VisibleForSerialization
	static final class KeyForWorkspace extends Key {

	private final Label label;
	private final int workspaceChunk;
	private final RootedPath workspacePath;

	private KeyForWorkspace(Label label, int workspaceChunk, RootedPath workspacePath) {
	this.label = Preconditions.checkNotNull(label);
	this.workspaceChunk = workspaceChunk;
	this.workspacePath = Preconditions.checkNotNull(workspacePath);
	}

	@Override
	Label getLabel() {
	return label;
	}

	int getWorkspaceChunk() {
	return workspaceChunk;
	}

	RootedPath getWorkspacePath() {
	return workspacePath;
	}

	@Override
	Key getKeyForLoad(Label loadLabel) {
	return keyForWorkspace(loadLabel, workspaceChunk, workspacePath);
	}

	@Override
	ASTFileLookupValue.Key getASTKey(Root root) {
	return ASTFileLookupValue.key(root, label);
	}

	@Override
	public String toString() {
	return label + " (in workspace)";
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (!(obj instanceof KeyForWorkspace)) {
	return false;
	}
	KeyForWorkspace other = (KeyForWorkspace) obj;
	return label.equals(other.label)
	&& workspaceChunk == other.workspaceChunk
	&& workspacePath.equals(other.workspacePath);
	}

	@Override
	public int hashCode() {
	return Objects.hash(KeyForWorkspace.class, label, workspaceChunk, workspacePath);
	}
	}

	/**
	* A key for loading a .bzl during {@code @builtins} evaluation.
	*
	* <p>This kind of key is only requested by {@link StarlarkBuiltinsFunction} and its transitively
	* loaded {@link BzlLoadFunction} calls.
	*
	* <p>The label begins with {@code @builtins//:}, but it is distinct from any .bzl in an external
	* repository named {@code "@builtins"}.
	*/
	@Immutable
	@AutoCodec.VisibleForSerialization
	static final class KeyForBuiltins extends Key {

	private final Label label;

	private KeyForBuiltins(Label label) {
	this.label = Preconditions.checkNotNull(label);
	}

	@Override
	Label getLabel() {
	return label;
	}

	@Override
	Key getKeyForLoad(Label label) {
	return keyForBuiltins(label);
	}

	@Override
	ASTFileLookupValue.Key getASTKey(Root root) {
	return ASTFileLookupValue.key(root, label);
	}

	@Override
	public String toString() {
	return label + " (in builtins)";
	}

	@Override
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if (!(obj instanceof KeyForBuiltins)) {
	return false;
	}
	return this.label.equals(((KeyForBuiltins) obj).label);
	}

	@Override
	public int hashCode() {
	return Objects.hash(KeyForBuiltins.class, label);
	}
	}

	/** Constructs a key for loading a regular (non-workspace) .bzl file, from the .bzl's label. */
	static Key keyForBuild(Label label) {
	return keyInterner.intern(new KeyForBuild(label, /isBuildPrelude=/ false));
	}

	/**
	* Constructs a key for loading a .bzl file from the context of evaluating the WORKSPACE file.
	*
	* @param label the label of the bzl file being loaded
	* @param workspaceChunk the workspace chunk that the load statement originated from. If the bzl
	* file is loaded more than once, this is the chunk that it was first loaded from
	* @param workspacePath the path of the workspace file for the project
	*/
	static Key keyForWorkspace(Label label, int workspaceChunk, RootedPath workspacePath) {
	return keyInterner.intern(new KeyForWorkspace(label, workspaceChunk, workspacePath));
	}

	/** Constructs a key for loading a .bzl file within the {@code @builtins} pseudo-repository. */
	static Key keyForBuiltins(Label label) {
	return keyInterner.intern(new KeyForBuiltins(label));
	}

	/** Constructs a key for loading the special prelude .bzl. */
	static Key keyForBuildPrelude(Label label) {
	return keyInterner.intern(new KeyForBuild(label, /isBuildPrelude=/ true));
	}
	}